An apparatus for separating bottles, etc., which uses a worm conveyor permits accurate feeding even under high performance conditions, simultaneously making it possible to increase the spacing distance in accordance with the requirements of the handling machine, which may be a filling or labelling machine, for example. A condition therefor is, however, that the vessels stand in a close line at the entry side of the worm conveyor and that there is a certain pressure caused by the accumulation of vessels at the entry side so that the vessels move on as continuously as possible into the "open" thread groove of the worm conveyor. Due to the play between the vessels and the worm conveyor or the guide means, respectively, which is indispensible to compensate for allowable variations in the vessel dimensions, heretofore a certain unsmoothness of the vessel movement before and at the entrance to the worm conveyor could not be avoided nevertheless, even if the thread design was optimal. This jerkiness causes adjacent vessels to bang each other or hit the worm conveyor and the guide means, which in turn results in a high emission of sound, so that the entrance to the worm conveyor of bottle handling machines represents a source of considerable noise. The noise level is particularly high, if the vessels being fed are not in full register with the initial pitch of the worm conveyor so that they meet the "closed" thread and are temporarily stopped. In this case, a great danger of fracture is incurred besides.
In one prior art apparatus of the type described hereinafore, the guide means is pivotally supported in the region adjacent the entrance to the worm conveyor and spring-biased (U.S. Pat. No. 2,692,671). If a vessel does not move into engagement with the worm conveyor accurately, the guide means can give way resiliently, whereby crushing or jamming of the respective vessel is avoided. Smoothening of the feed movement of the vessels and, thus, a reduction in sound emission cannot be obtained by such resilience of the guide means, however. Furthermore, in this prior art apparatus, the worm conveyor itself is made somewhat resilient in that a jacket of relatively hard rubber which forms the thread is mounted around a metal core. This provision also serves to avoid damaging of the vessels, especially scratching thereof. The sound emission caused by vessels banging each other may possibly be somewhat reduced by this worm conveyor also, but it is not possible thereby to smoothen the feed movement of the vessels, leave alone compensate for varying distances between the vessels being fed. Added to this is the fact that the resilient jacket will be destroyed by fed pieces of broken vessels or fractured bottles particularly quickly, since the pieces of broken vessels can get jammed between the jacket and the conveyor belt. Therefore, this prior art apparatus does not satisfy the practical demands with regard to service life and operating reliability.
In another prior art vessel separating apparatus, the guide means which is opposed to a worm conveyor is in the form of a second worm conveyor or a rotating roller (German Pat. No. 1,091,940) which corresponds to U.S. Pat. No. 2,890,787. In the exit region of the second worm, between the thread groove receiving the vessels or the end portion of the roller, respectively, spirally arranged bristles are mounted for urging the vessels into engagement with the thread groove of the worm conveyor, thereby giving stability to the vessels. These bristles have no conveying or spacing function whatsoever, nor are they capable of damping the shocks occurring at the entrance to the worm conveyor.
The task underlying the present invention is to provide an apparatus of the aforementioned type which has a sufficiently wear-resistant worm conveyor and enables substantially smooth and low-noise feed of vessels.
The apparatus according to the invention is distinguished over a worm conveyor having a one-piece jacket of resilient material in that greater resilience and increased wear-resistance can be obtained owing to the fact that the resilient jacket is divided into a great number of individually resilient separate elements made of a suitable material chosen for the purpose. It is easily possible to use materials having excellent wear resistance properties, such as metal or tough-elastic plastic, e.g. polyamides. Irrespective of this, the desired resilience can be influenced by the shape of the individual elements.
In a further embodiment, the individual elements themselves may easily be made of a hard material, the desired resilience then being provided by spring members. Each individual element can be separately mounted on the core by a spring member of its own or the individual elements may back against each other directly, with a spring member interposed respectively.
In a further embodiment, the lamellas are preferably made of tough-elastic plastic and are provided in the radially inner portions thereof with extensions acting as spacer members, whereby their edge portions which define the thread groove are freely movable.
One embodiment is particularly advantageous, namely, the resilient individual elements being movable in all directions so that the entrance region is resiliently yieldable in the direction of transport, in a direction transverse to the direction of transport and in the circumferential direction. Thereby, optimum shock absorption and, thus, a particularly smooth entry of vessels are enabled. Sufficient wear resistance can be obtained nevertheless, as, for instance, by using round bristles made of a polyamide material, and the apparatus becomes substantially insensitive to the feeding of pieces of broken vessels or fractured bottles and the improper feeding of vessels.
A particularly useful embodiment includes a two-part design of the screw conveyor which is normally quite sufficient to provide good shock absorption in the entrance area. The two-part design finds particular utility, if following the separation of vessels a strong acceleration to increase the distance takes place, which can be brought about by the rigid worm body alone.
One embodiment of the invention also affords considerable advantages in practical operation. In case of fatigue of the resilient elements, it is not necessary to replace the entire worm, but merely the entrance portion with the individual resilient elements, which is particularly susceptible to wear, etc., anyway. In this case, the solid worm body can be used much longer than conventional one-part worm conveyors, since it is stressed to a much lesser degree. A possible increased wear of the part disposed at the entrance side, which comprises the individual resilient elements, is more than compensated thereby.
Owing to the great yieldability of the entrance region, especially if bristle-like individual elements are used, the apparatus according to the invention can easily cope with minor deviations from the nominal separation or spacing of the vessels fed by the conveyor belt. In this apparatus, the operation of which involves particularly little noise, the accumulation pressure which is necessary to cause the bottles to close up is received by the gate member disposed upstream of the worm conveyor. This gate member can be, for instance, a star-shaped transport organ which rotates in synchronism with the worm conveyor and passes the vessels on to the worm conveyor in such a way that the vessels are already somewhat spaced and, thus, not in contact with each other. The gate member can be positioned either directly adjacent the conveyor belt that leads to the worm conveyor or adjacent another conveyor belt provided upstream of this conveyor belt and moving at a somewhat lower velocity. The vessels, which are already somewhat spaced when arriving at the worm conveyor, are received thereby gently and smoothly, even if the distance between them should have changed a little in the meantime, and the worm conveyor places them at the desired final distance which they have when arriving at the handling machine.